scheduling lecture Flashcards
a CPU bound process spends almost all of its time in a
ready or running state
an I/O bounds process spends almost all of its time in a
sleep / waiting state
when will a CPU make scheduling decisions when a process:
- switches from running to waiting
- switches from running to ready state (pre-emptive)
- switches from waiting to ready (pre-emptive)
- terminates
A non pre-emptive algorithm makes a scheduling decision when a process:
- terminates
- requests an unavailable source
function of a dispatcher module
gives control of the CPU to the process selected by the short-term scheduler
- switching context, switching to user mode, jumping to the proper location in the user program to continue executing that program
Waiting time is defined as
the time a process spends in ready state
turnaround time is defined as
how long it takes to finish a given process
response time is defined as
how quickly the process begins producing output
FIFO / FCFS
- non preemptive, process holds until it blocks, yields or terminates
SJF
- minimizes the average waiting time of a process
- predicts the length of the processes’ next CPU burst using historical data